Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Mitsuru Hiki,A Study on So-called Optional Article Usage:When Is It That It Doesn′t Really Matter Which Article to Use?,名古屋市立大学教養部紀要 人文社会研究,03891356,名古屋 : 名古屋市立大学教養部,1996-03,,42,29-57,https://cir.nii.ac.jp/crid/1520853832012596608,